In recent years, the application of so-called optical interconnection has become wide-spread as a technology for transmitting signals at high speed within a system device, between devices, or between optical modules. Here, optical interconnection refers to a technology in which optical components are handled as if they are electronic components, and are mounted on motherboards, circuit boards, and the like used in personal computers, vehicles, optical transceivers, and the like.
An optical module used in optical interconnection such as this serves various purposes, such as internal connection for media converters and switching hubs, and in-device and inter-device component connection for optical transceivers, medical equipment, testing devices, video systems, high-speed computer clusters, and the like.
As an optical component applied to this type of optical module, there is an increasing demand for a lens array in which a plurality of lenses having a small diameter are disposed in an array, as a compactly structured component effective for actualizing multichannel optical communication.
Here, the lens array is conventionally configured such that a photoelectric conversion device including a plurality of light-emitting elements (such as a vertical cavity surface emitting laser [VCSEL]) can be attached thereto, and a plurality of optical fibers serving as an optical transmission body can be attached thereto.
In a state in which the lens array is disposed between the photoelectric conversion device and the plurality of optical fibers in this way, the lens array optically couples light emitted from each light-emitting element of the photoelectric conversion device with an end face of each optical fiber. As a result, multichannel optical transmission can be performed.
In addition, among photoelectric conversion devices, there is a photoelectric conversion device that includes, together with the light-emitting elements, light-receiving elements that receive light including communication information that is carried through the optical fibers and emitted from the end faces of the optical fibers, to support optical transmission and reception (bidirectional communication). A lens array supporting a photoelectric conversion device such as this couples the light emitted from the end faces of the optical fibers with the light-receiving elements.
Furthermore, among photoelectric conversion devices, there is a photoelectric conversion device that includes monitor light-receiving elements that are used to monitor light (particularly intensity or amount of light) emitted from the light-emitting elements, to stabilize output characteristics of the light-emitting elements. A lens array supporting a photoelectric conversion device such as this reflects a portion of the light emitted from the light-emitting elements towards the monitor light-receiving element side as monitor light.
As a lens array supporting optical transmission and reception that includes a reflection function for generating the monitor light such as this, the inventors of the present invention have made proposals in the past, such as that in Patent Literature 1.